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" TURBO BUILDS " Post your Turbo build-Up or any that you have in process

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Old 05-05-17, 09:43PM   #1
Nascar-TA
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Default Best Pontiac Motor For Turbo?

Hello question for you Pontiac Turbo Pros. All Pontiac V8's have the same bore spacing for 326 through 455 with similar cylinder wall thickness. Correct? I know that cooling is very important with forced induction. A mater of fact, I know a certain OEM that reduced their engine size in order to improve the cooling between the cylinder bores. True there is no replacement for displacement, but what do you think?
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Old 05-05-17, 09:55PM   #2
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Im happy with my 462 but I have been thinking about a 406 for my next build. The 400 block is stronger and I already have a set of ported 6x-4 heads so I can run flat top pistons. I have a s480 on my 351w in my Capri and a small cube motor can be equalized with boost.

But my 462 has been running with the s475 for 10 years now....... Damn thing just keeps going. lol.
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Old 05-05-17, 10:06PM   #3
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My opinion is the 440 cid. 428/455 hybrid does everything well.
Mine ran better than my 455 variants but I still have the 440s cam in my 455 so maybe if I optimized the cam for my 455 I'd like it better who knows.

The 440 was an animal though,


As for cooling being important cooling is actually better on most turbo applications due to the engines lower compression ratio when not under boost making it easier to cool with lower btu's being produced. Mine cools instantly to 160 in traffic which my N/A engines at 10+ to 1 compression never were able to achieve.

If your tune is good your EGTs shouldn't be any higher than a N/A engine of the same HP

Of course not many N/A engines can achieve the horsepower of a turbo engine ��
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old set up-3250 LBS 69 firebird T-88 turbo 455 .030 CAT H beam rods, stock crank, stock block( 2 bolt) performer intake, 850 carb 6X-6 heads 114 cc ( unported) TH 400 and 3.73 gears = 9.76 @ 141 with a 163 short time = 725 RWHP and 878 HP @ the crank

new set up - same but with home ported heads and Gen 7 DFI, my custom SS headers
Jeff Palazzo

Www.pontiaction.net
Www.mayhemturbo.com
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Old 05-05-17, 10:09PM   #4
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70bird it's amazing how these things just keep on going if the tune is right. I think, I'm on 9'years I'd actually have to do the math, but I have never even changed the spark plugs.��
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old set up-3250 LBS 69 firebird T-88 turbo 455 .030 CAT H beam rods, stock crank, stock block( 2 bolt) performer intake, 850 carb 6X-6 heads 114 cc ( unported) TH 400 and 3.73 gears = 9.76 @ 141 with a 163 short time = 725 RWHP and 878 HP @ the crank

new set up - same but with home ported heads and Gen 7 DFI, my custom SS headers
Jeff Palazzo

Www.pontiaction.net
Www.mayhemturbo.com
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Old 05-06-17, 03:31PM   #5
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Quote:
Originally Posted by turbo69BIRD View Post
My opinion is the 440 cid. The 440 was an animal
Thanks for the input! Now would you do the 428-440 using a 400 block in order to get the smaller main bearing or would you use a 428 block?

What do you think of the 4 inch bore with a 3 inch stroke and a 6 inch rod?
Another question, can you have a loopy cam with a turbo? I love the sound, even of a small one.
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Old 05-07-17, 01:34PM   #6
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You want it to last forever, buy an a/m block. No need for a big stroke. heads don't have to be great either unless you want massive power.
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Old 05-07-17, 01:54PM   #7
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Quote:
Originally Posted by Nascar-TA View Post
Thanks for the input! Now would you do the 428-440 using a 400 block in order to get the smaller main bearing or would you use a 428 block?

What do you think of the 4 inch bore with a 3 inch stroke and a 6 inch rod?
Another question, can you have a loopy cam with a turbo? I love the sound, even of a small one.
I don't feel there's any need for the smaller main Bearing if your not spinning it high. I shift at 5800 plenty of longevity in my set up. Mine was a 428 block and I loved that engine, I split a cylinder when I turned it up to 30 psi with 10.5 to 1 compression on my first turbo outing, learned fast about boost greed. Lmao That engine had a TON of track passes on it as a naturally aspirated engine before too. Probably was 4 + years old at 160 track passes a year. And the rotating assembly was used out of my buddy's car with god knows how many passes on it before that.

It went 122 mph in the 1/8 though so it was on a nice run., ran 10 flat for the first 3 runs off the trailer though on a new ( completed soup to nuts in 48 hours including building the headers) build so couldn't complain too much. It was carberated, no intercooler and completely not optimized.

My cam sounds quite lopey and it's got very little overlap so you don't have to give that sound up, that being said it'll be more manageable if it's not as far as street manners.

I don't really like anything exotic for combos too much of a pain, I like the kiss rule.
The simpler the better for me.

As for an aftermarket block, I've heard more people have issues with aftermarket than stock personally. GM did a lot of R&D and they put more money and testing into their products than any after market company can or will so I run stock items mostly but modified to my needs. Unless it's something like con rods which were just junk thanks to the bean counters. But they worked for their mission of 3500 rpm daily drivers.
Jspont is just mad at his block right now ��
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old set up-3250 LBS 69 firebird T-88 turbo 455 .030 CAT H beam rods, stock crank, stock block( 2 bolt) performer intake, 850 carb 6X-6 heads 114 cc ( unported) TH 400 and 3.73 gears = 9.76 @ 141 with a 163 short time = 725 RWHP and 878 HP @ the crank

new set up - same but with home ported heads and Gen 7 DFI, my custom SS headers
Jeff Palazzo

Www.pontiaction.net
Www.mayhemturbo.com
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Old 05-07-17, 03:55PM   #8
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LMAO! Trust me there is a limit to the stock blocks. Even though the aftermarket blocks need a lot of machine work, if you are looking for big power, Over 1500 h.p. there is no issue. All the real wicked fast Pontiacs run an A/m block.
For street use the stock block is fine. I can give you and example.

A 65 389 standard bore vs. a 1970 400 block. (even with the 389 small bore and more cylinder thickness) the 400 is 16 lbs heavier. The mr1 block is 49 lbs heavier than the 400.
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Old 05-08-17, 11:47AM   #9
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All that proves is it's a better paperweight.
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old set up-3250 LBS 69 firebird T-88 turbo 455 .030 CAT H beam rods, stock crank, stock block( 2 bolt) performer intake, 850 carb 6X-6 heads 114 cc ( unported) TH 400 and 3.73 gears = 9.76 @ 141 with a 163 short time = 725 RWHP and 878 HP @ the crank

new set up - same but with home ported heads and Gen 7 DFI, my custom SS headers
Jeff Palazzo

Www.pontiaction.net
Www.mayhemturbo.com
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Old 05-08-17, 11:54AM   #10
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Yes people break blocks , they also born pistons and of all kinds of other things but is it the tune or the block? Mine was the TUNE when I split a cyl. Not the block.

Lots of people like to blame parts and sometimes the parts do have an issue. ( usually after market )
I can think of Alot of guys who have had issues with porosity on cyl heads , funny my iron Pontiac heads don't haves those issues, but anyone around will tell you you can't run a 6x iron head and make any power.

All I know is I run a lot of iron Pontiac parts people would say are junk. My car has been far from a street car and I've made it last and run hard.
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old set up-3250 LBS 69 firebird T-88 turbo 455 .030 CAT H beam rods, stock crank, stock block( 2 bolt) performer intake, 850 carb 6X-6 heads 114 cc ( unported) TH 400 and 3.73 gears = 9.76 @ 141 with a 163 short time = 725 RWHP and 878 HP @ the crank

new set up - same but with home ported heads and Gen 7 DFI, my custom SS headers
Jeff Palazzo

Www.pontiaction.net
Www.mayhemturbo.com
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Old 05-08-17, 12:53PM   #11
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Im not an expert. I'm learning as I go. I have an IA2 4.350 bore. I bought it used so the bore size was already set. If I had the option of bore size I would have went 4.200. Leave more deck between the cylinders to handle more boost some day.

I have a 1969 400 block that was converted to 4 bolt and had the lifter valley braced. I would no hesitate to drop another good 4" crank in that dude and turn the boost up. It would handle 1000 in a Turbo build. The cost however to have a good competent machine shop to do the 4 bolt conversion and get this block ready was not much cheaper then just going with IA2 to start with.
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Best pass so far 9.65 @ 140. 1.41 60 ft.
4 lbs boost on t-brake. 14 lbs going down the track.
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